Basic Elementary Question (s) on Flats and Calibration

[Roger Baylon]

Question 1-

When I want to use ACP to calibrate images at the time they are acquired, I have been copying an AutoFlat folder and a Calibration folder into the ACP images folder for that night.
Is this step necessary?
I seems to work, but maybe there is a much, much easier way?


Question 2-

In the attached image (M81), the ACP calibration has attempted to correct a large circular area in the lower left. Either the diameter of the flat correction is a little too small, or a little too large. But in any case it leaves a ring --instead of the uncorrected circular area -- as the net result.
Does this mean that I may have specified something incorrectly somewhere, like pixel size, etc? This "artifact" only shows up by setting the Levels gamma to .5 or below.

In the past, I have rarely used gamma settings below .7 to get a useful image--so maybe I am worrying about a non-issue.

Warmly, Roger